My puppy has become snappy with larger dogs

Last weekend I brought my 6 month old Australian shepherd to the dog park for the first time, before then she has been going to doggy day care multiple days a week and has been doing great! She plays with every dog no matter the size and has never been snappy but that day I brought her to the dog park everything was going great then some people came in with their Belgian malinois and German shepherd then the malinois kept getting in her space and bit her pretty hard I don’t think it was out of aggression I think he was just playing too rough but after that the owner pulled him away then it happened again and she started snapping at him and hiding then we left and made sure not to make a scene about it and just walked her around to try and help her like shake it off and move on but today we took her to the dog park again and a larger dog was there and every time he approached her trying to play she would start snapping at him and hiding behind me, she did try to run around with him and play then she got scared and did it again, like she wanted to play but was also afraid and didn’t know how to react and she has never done that before and I’m afraid she’s been traumatized from the malinois. How do I help her to not be snappy anymore so she won’t act this way with dogs larger than her? (fyi she’s been to day camp once after the first time at the dog park and was perfectly fine)